1. Field of the Invention
The present invention relates to a micromechanical component and a production method for a micromechanical component.
2. Description of Related Art
A micromechanical component often has an element that is adjustable in relation to a holder of the micromechanical component. In addition, the micromechanical component may have an evaluation device which is configured to establish information regarding a current position of the adjustable element in relation to the holder.
A conventional evaluation device includes, for example, an optical sensor including a light source for emitting a light beam, which is directed onto a reflective surface of the adjustable element, and a detector for determining the point of impingement of the light beam reflected at the reflective surface. An optical sensor of that kind, however, is relatively expensive and requires a relatively large amount of installation space. Furthermore, the evaluation method for evaluating the values provided by the optical sensor is comparatively complicated.
As an alternative to the optical sensor, the evaluation device may also have a capacitive sensor. In that case, the adjustable element includes a first electrode. A capacitance between the first electrode and a second electrode which is fixedly situated on the holder allows inferences to be made regarding the current position of the adjustable element in relation to the holder. An evaluation device having such a capacitive sensor does, however, require costly electronics to filter out interfering signals. Furthermore, applied voltages of an electric drive for adjusting the adjustable element in relation to the holder may lead to measuring errors of the capacitive sensor.
In addition, measuring methods are known from the related art in which a spring, via which the adjustable element is connected to the holder, is equipped with a piezo-resistive sensor element. Frequently, adjustment of the adjustable element in relation to the holder causes mechanical stresses to be applied in that case to the piezo-resistive element. A sensor signal provided by the piezo-resistive sensor element is altered by the mechanical stresses.
To perform such a measuring method, however, it is necessary for the piezo-resistive sensor element situated on or in the spring to be electrically connected by electrical supply and/or detection lines. This frequently leads to problems, especially when at least two piezo-resistive sensor elements are used for determining a change in the current position of the adjustable element in at least two directions in space. According to the related art, in the case of such a measuring method a first piezo-resistive sensor element is situated on or in a first spring and a second piezo-resistive sensor element is situated on or in a second spring. As a rule, the first spring is twisted upon adjustment of the adjustable element about a first rotation axis. Correspondingly, the second spring is twisted as soon as the adjustable element is adjusted in relation to the holder about a second rotation axis.
If the first spring is in the form of an outer spring and the second spring is in the form of an inner spring, the supply and/or detection lines of the second piezo-resistive sensor element have to be routed, however, via the first spring. It is hardly possible to do that, especially in the case of narrow springs having a width of less than 50 μm. In addition, the supply and/or detection lines of the second piezo-resistive sensor element may be damaged upon bending of the first spring, especially if they are made of aluminum. Furthermore, the supply and/or detection lines of the second piezo-resistive sensor element which are routed via the first spring generally reduce the adjustability of the adjustable element about the first rotation axis.